Fuel Injectors for 320HP Monsoon 5.7L engine

[MoonDawg]

I have a 1996 Response LX and it is time to replace the Fuel injectors.  I called my local Malibu dealer and they were fresh out of ideas on what Fuel Injectors to use as a replacement for the original Rochester 17095004, 24 lbs/hr Fuel Injectors. Rochester became Delphi and they don't seem to make a direct replacement.

Has anyone replaced their injectors with GM 19244617 Fuel Injectors. They are pricey at  $85-$100 each but probably well worth it if they are a direct replacement. The manufactures don't provide enough information to determine if they will work.

I did find that 1999 Prostar LTRs came with GM 19244617 fuel injectors in their Indmar engines so I am leaning toward that direction.

 

The Bosch 211U267 EV-6 Fuel Injector is listed as a replacement for GM 19244617 but to make it fit it probably requires a sleeve (Bosch dia is 0.65 and GM is 0.9)

Bakes sells an Indmar EV-14 injector but it probably also needs a sleeve but at $34 it may be worth the effort.

 

What have others done?

 

 

[oldjeep]

Any reason not to just have them rebuilt?

[Bozboat]

As OJ mentioned, Send them out to be rebuilt and matched, one week turn around and should be less than $250 (plus covid fee) 

[MoonDawg]

They are 25 years old and rusty... New Bosh injectors have a 4 nozzle design. What if someone asked me how many nozzles I had on my injector and I had to say three...(That 's a joke)? 

[justgary]

47 minutes ago, MoonDawg said:

They are 25 years old and rusty... New Bosh injectors have a 4 nozzle design. What if someone asked me how many nozzles I had on my injector and I had to say three...(That 's a joke)? 

I agree on sending yours off for cleaning, but if you must replace them, do not buy injectors that require an adapter.  Plenty of options allow direct replacement. 

Here are a few threads on the topic:

 

[MoonDawg]

I read through the threads, the last one was good but made a leap from Indmar part number: I556049 to Bostech MP3022 based on a visual evidence (no cross-reference). 

I am thinking that I will go with the GM 19244617 part. The worst that could happen is that I would have to buy a new GM MPI intake manifold. The one I have on the Indmar Monsoon 320HP is a Cutter. If I stick with GM parts they should at least fit.

 

[justgary]

1 hour ago, MoonDawg said:

I read through the threads, the last one was good but made a leap from Indmar part number: I556049 to Bostech MP3022 based on a visual evidence (no cross-reference). 

I am thinking that I will go with the GM 19244617 part. The worst that could happen is that I would have to buy a new GM MPI intake manifold. The one I have on the Indmar Monsoon 320HP is a Cutter. If I stick with GM parts they should at least fit.

 

The whole point in most of the threads here is that the GM replacements *don't* fit.  Visual evidence is appropriate since that is the only difference. 

I'm pretty sure that they are all 12 Ohm, 3 Bar, 24 Pound per Hour injectors.  The difference is that some of them have a shorter nipple than others, and won't fit the manifold without an adapter.  Maybe your manifold is already designed for the shorter parts, so it won't be a problem to you.

The Bostech injectors are remanufactured, so I suppose they could be either original GM or aftermarket parts.  I would personally rather send mine off for cleaning than blindly replace them all with remanufactured ones.

BTW, I did notice that you mentioned the four-hole injectors and a different manifold.  Are you chasing peak horsepower for some reason?  While that might be a worthy goal for racing, it can't possibly matter if you don't run the engine wide open (and thereby use the maximum output).  Anything less than maximum output is already obtainable without extra effort or cost on your part.

[Brettski]

I have a 2005 Mustang GT and had issues with my fuel injectors causing rough idling and poor fuel economy. I was looking at replacements and the dealer suggested the Ford Racing injectors, but they were quite expensive. 

I stumbled upon some injection pump deals during my search and ended up getting the Bosch 0280158117 injectors for around $50 each, which was a great price compared to the dealer's quote. These injectors fit perfectly and improved my car's performance and fuel efficiency. They worked seamlessly without needing any additional modifications or parts.

Edited March 25 by Brettski

[kcpilotpat]

I am fighting bad injectors now on a 2002, 5.7 Indmar MPI and this will bring the thread up to date on what I found.  The rescue boat I'm working on has been sitting 2.5 years so many gremlins lurking.  I drained the fuel, flushed the tank replaced the fuel pump, and flushed the rails. I started right up and ran poorly.  I pulled the injectors and the screens were full of rust. I had them cleaned and checked locally and they were returned with a test sheet saying they all are within spec.  It ran much better, but I could tell it wasn't right and it loped at idle a lot and would eventually die.   I did the trick of pulling the injector wires while driving the boat at moderate power and 3 cylinders weren't hitting.  I moved the injectors around and the dead cylinders moved with the injectors.   I decided to replace the injectors but I couldn't find what to order.  I searched the net and called the dealer.  I called Indmar and got the right guy on the phone.  The injector is a Rochester part number is 19244617.  They are a 250 cc or 24 lb/hr injector as mentioned above. He said somewhere along the line GM changed the diameter of the hole in the intake manifold and I may have to ream out the holes a bit.  He said this can be done with the manifold left on.  Use a shop vac while reaming to pull the cuttings up. 

The boat motor uses fuel injection technology from the early 90's.  Because boat motors don't have mass air flow and exhaust sensors for feedback they don't use modern systems.

One of the companies I talked to in the process was RC Fuel Injection; they were very helpful.  They offered to check my injectors and advise me on the correct flow rate.  When I got the part number they could provide a close injector.  I ordered a full set of these. They are 23#/hr injectors. It is considered a performance injector and was less than replacements from the auto store. We will see if they fit and if it fixes the problem. 

https://www.rcfuelinjection.com/Store/c/performance-injectors/p/sl2-0240-saturated-injector

[justgary]

I'm not sure I would use 23#/H injectors in place of 24#/H in an engine with no feedback.  My understanding is that the fuel map is intentionally rich, but I don't know how much.  Running the engine lean is asking for trouble.

[electricjohn]

That would take the stoichiometric air/fuel ration from 14.7 to 1, up to 15.3 to 1 on an open loop (non lambda) FI engine.

[kcpilotpat]

Well, we shall see on the flow rate.  I was excited to find something that close.  Too add to task, the injetors don't fit.  When I talked to the tech at Indmar, he explained somewhere along the line the pilot on the injector was enlarged by GM.  He expected that my year would be one of them affected.  He advised reaming the hole using a shop vac to collect the cuttings.  The injector hole in the intake is stepped. The smallest hole is for the seal.  This size matched. There is a pilot above the seal. The OD of pilot of the replacement injectors is 5/8".  The hole in my manifold and the pilot on the old injectors were 1/32 under.   That step is in process now.  I will grab some photos.

[roeboat]

On 5/4/2024 at 11:00 PM, kcpilotpat said:

Well, we shall see on the flow rate.  I was excited to find something that close.  Too add to task, the injetors don't fit.  When I talked to the tech at Indmar, he explained somewhere along the line the pilot on the injector was enlarged by GM.  He expected that my year would be one of them affected.  He advised reaming the hole using a shop vac to collect the cuttings.  The injector hole in the intake is stepped. The smallest hole is for the seal.  This size matched. There is a pilot above the seal. The OD of pilot of the replacement injectors is 5/8".  The hole in my manifold and the pilot on the old injectors were 1/32 under.   That step is in process now.  I will grab some photos.

I ran into the same issue with replacement fuel injectors. I bought FJ164 injectors and had the same problem with the enlarged pilot. Instead of boring the manifold, I used emery cloth on the pilot to get it to the right size.  It took a few hours, but it saved me from risking metal shavings in my intake.

[justgary]

23 hours ago, roeboat said:

I ran into the same issue with replacement fuel injectors. I bought FJ164 injectors and had the same problem with the enlarged pilot. Instead of boring the manifold, I used emery cloth on the pilot to get it to the right size.  It took a few hours, but it saved me from risking metal shavings in my intake.

In your opinion, would it be possible to chuck an injector in a lathe and turn the pilot stem down a bit?

[roeboat]

2 hours ago, justgary said:

In your opinion, would it be possible to chuck an injector in a lathe and turn the pilot stem down a bit?

I think it would be possible, but it depends on the kind of lathe you have. You would definitely have to chuck it on the metal part of the injector, or you run the risk of separating plastic and metal parts of the injector. The ideal place to chuck it would be on the larger metal side, if you can clear the connector, but I don't think it would be possible. So, then you have to chuck it in the side with nozzle, which means it would be hard to cutting tool in.

Long story short. Yes, it would be possible with the right tools.

[justgary]

10 hours ago, roeboat said:

I think it would be possible, but it depends on the kind of lathe you have. You would definitely have to chuck it on the metal part of the injector, or you run the risk of separating plastic and metal parts of the injector. The ideal place to chuck it would be on the larger metal side, if you can clear the connector, but I don't think it would be possible. So, then you have to chuck it in the side with nozzle, which means it would be hard to cutting tool in.

Long story short. Yes, it would be possible with the right tools.

So just to be clear, you are talking about the larger diameter (in red).  It sounds like from your and @kcpilotpat's descriptions that the hole is 15mm and the JF164 injectors are 5/8", so turning about 0.035" off the diameter should do it.  My little lathe (a 6" Atlas/Craftsman) is the tool of choice for this kind of job.  Thanks for the information!

 

[roeboat]

The part I am talking about is what I circled in red. That is the part that needs to be turned down. The part you put in red sits above the intake manifold. 

[justgary]

10 minutes ago, roeboat said:

The part I am talking about is what I circled in red. That is the part that needs to be turned down. The part you put in red sits above the intake manifold. 

Thanks for clarifying.  That part is a bit more pesky to turn, but maybe it would work with a collet to hold the small end. 

It would be nice to get all of this settled so we know exactly what to do when we need new injectors.  I would certainly rather modify the new parts than the old engine, but that's just how I was trained.

[roeboat]

Same, who knows maybe the next time I need new injectors someone will make ones that fit!

[agetech30]

I had this problem last year on my monsoon.  I just rolled the area circled in red around a 6" bench grinder.  Doesn't take much work.  Kinda messes up the injector but you can't see that.  Used a caliper to check the diameter.  Doesn't affect sealing.

The metal lathe should work great.

 

[justgary]

14 hours ago, agetech30 said:

I had this problem last year on my monsoon.  I just rolled the area circled in red around a 6" bench grinder.  Doesn't take much work.  Kinda messes up the injector but you can't see that.  Used a caliper to check the diameter.  Doesn't affect sealing.

The metal lathe should work great.

 

And you also used FJ164 injectors, or another part number?

[agetech30]

All the new injectors are the same standard diameter.  Just a little big for the older manifolds.  I'll try to find the part # for the injectors I used.

[agetech30]

The injectors in the pictures look like the ones I used, I think I ordered 24.5lb injectors since I was putting in the ZZ4 cam.